While regulatory agencies continue to debate how it will be implemented, only one thing is certain about a provision that allows a 400-pound weight exemption for auxiliary power units: it has left many truckers confused.

The exemption, which was signed into law by President Bush in August 2005 as part of the Energy Policy Act of 2005, increases a vehicle’s maximum gross vehicle weight limit and axle weight limit by 400 pounds. This allows for the adding of a qualified idle-reduction technology, such as an APU.

The Federal Highway Administration announced a “notice of proposed rulemaking” in the Federal Register on May 1 to solicit comments from the public. That comment period ended June 30. If the rulemaking is approved, the exemption would modify Title 23, Section 127(a) of the U.S. Code, which deals with size and weight allowances.

Specifically, the rulemaking

requires – by demonstration and/or certification from the manufacturer – that the idle-reduction technology “is functional at all times, does not exceed 400 pounds gross weight (including fuel), and that the unit cannot be used for any other purpose.”

However, even if the rulemaking is approved after the comment period, a memo written by FHWA’s Size and Weight Division in November 2005 indicates that the exemption won’t be treated as a federal mandate.

“We determined that (the exemption) does not pre-empt state regulations or compel the states to grant the increased weight tolerance,” the FHWA memo said. “Rather, (the exemption) simply increases the federal interstate maximum weight limits to compensate for the weight of the APUs installed.”

OOIDA has filed comments regarding the rulemaking, with particular concern for the fact that an APU that breaks down would not meet the exemption’s qualifications.

“I think one of the things we’re arguing is, what if the APU quits working?” said Rick Craig, director of regulatory affairs for OOIDA. “If it’s not working, would they cite you for being overweight? What are you supposed to do – the minute it quits working, remove it and ship it in for repairs?”

Environmental Protection Agency officials also voiced their concern over an exemption that would not be honored nationwide.

“The non-preemptive nature of the 400-pound weight waiver creates a disincentive for trucking companies and owner-operators to purchase and use mobile idle-reduction technologies,” an internal EPA memo stated. “Truck owners have no way of knowing whether … a particular state may issue them a citation for their APU weight.”

Land Line has received reports from truckers that enforcement officials in several states are not acknowledging the higher limit, including Florida and Nebraska. Officials with some states, however, told Land Line and OOIDA’s Member Assistance Department that they were not explicitly acknowledging the exemption, but that their weight tolerances would cover an additional 400 pounds.

Although some states are not following the measure, the state of Oregon has gone public with its support. Oregon DOT’s Motor Carrier Division agreed to allow the additional weight, even before the legislature considered adding the language to the state’s own law books.

Supporters within the trucking industry said that without nationwide support, the higher weight limit is useless to truckers who do interstate business.

“We’re trying to do good by the environment, but we’re also trying to do good by our bottom-line business practices. We’re trying to conserve fuel when fuel is at this high price,” said Mike Joyce, senior government affairs representative for OOIDA. “And somebody fining us for their interpretation, their state’s desire not to participate in the program, is counterproductive to what we think the intentions of the members of Congress were.”